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The Rf value for each spot should be calculated. Rf stands for "ratio of fronts", or "retardation factor", and is characteristic for any given compound on the same stationary phase, using the same mobile phase for development of the chromatogram. Hence, known Rf values can be compared to those of unknown substances to aid in their identifications.
(Note: Rf values often depend on the temperature, solvent, and type of stationary phase used in the experiment; the most effective way to identify a compound is to spot known substances next to unknown substances on the same chromatogram.)
In addition, the purity of a sample may be estimated from the chromatogram. An impure sample will often develop as two or more spots. If a sample develops as only one spot it may or may not be pure. The sample may contain another compound which did not separate under the conditions of the experiment. Purity of samples is often determined in conjunction with other techniques,
such as measuring a sample's melting point or recording its nuclear magnetic resonance spectrum.
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